The present invention relates to a manufacturing device of a clutch cover assembly and a manufacturing method of the same, which is used in a friction clutch of a diaphragm spring type for automobiles and others.
Generally, in a clutch of a diaphragm spring type, a diaphragm spring for forcing a pressure plate is supported by projections or tabs of a clutch cover through wire rings which form fulcrums of the diaphragm spring. However, in manufacturing of such a clutch cover assembly, as shown in FIG. 3, a plurality of the projections 2 integrally formed at the inner periphery of the clutch cover 1 are bent by a hydraulic press device 3 to support the inner peripheries of a pair of the wire rings 5 and 6, and then ends 7 of the projections 2 are further bent by the press device 3 so that the ends 7 may hold the sides opposite to a diaphragm spring 8 of the wire rings 5 and 6.
However, in the conventional press device 3, a lower die 10 of the device 3 is desgned to support only a lower surface of an annular body 11 of a clutch cover 10, and an upper die 12 is designed to push the projection ends 7 downwardly while supporting a radially inner side of each projection body 9 through its whole length by support portions 14. Therefore, in the conventional upper die 12, it is necessary to provide the long projected support portions 14 which are longer than the projection bodies 9, and these long supports 14 receive a large bending moment from the work piece. Therefore, the support portions 14 of the conventional upper die 12 may be broken, which causes interruption of the work. Further, the bending accuracy can not be increased sufficiently because the support portions 14 deform. Moreover, the support portions 14 must be long projections to be extended downwardly through openings 15 in the spring 8. Moreover, the whole support portions 14 have complicated shapes, resulting in a high manufacturing cost.
Accordingly, it is an object of the invention to provide a structure and a manufacturing method, overcoming the above-noted disadvantages, in which portions of projections at free end sides positioned above a diaphragm spring are adapted to be supported by a upper die and portions of the projections at base end sides positioned below the diaphragm spring are adapted to be supported by a lower die.
Other and further objects, features and advantages of the invention will appear more fully from the following description of the preferred embodiments of the invention.